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This study was undertaken to investigate the effects of the administration of 3,4-methylenedioxymethamphetamine (MDMA) on the locus coeruleus firing rate, on the sensitivity of the α2-adrenoceptors which regulate neuronal activity and on the in vivo tyrosine hydroxylase activity in hippocampus. The basal firing rate was not modified by either a single dose or repeated doses of MDMA, although the latter produced a shift to the right in the dose-response curve for clonidine-induced inhibition of the firing rate (ED50 increased by 59%) and a reduction in tyrosine hydroxylase activity (20%) in the hippocampus. However, 8 days after the final dose α2-adrenoceptor sensitivity and tyrosine hydroxylase activity had returned to control values. Our results show a desensitization of α2-adrenoceptors in locus coeruleus and the existence of short-term changes in the noradrenergic system. [Copyright &y& Elsevier]

Abstract: Metabolites of dopamine and norepinephrine measured in the plasma have long been associated with symptomatic severity and response to treatment in schizophrenic, bipolar and other psychiatric patients. Plasma concentrations of catecholamine metabolites are genetically regulated. The genes encoding enzymes that are involved in the synthesis and degradation of these monoamines are candidate targets for this genetic regulation. We have studied the relationship between the Val158Met polymorphism in catechol O-methyltransferase gene, variable tandem repeat polymorphisms in the monoamine oxidase A gene promoter, and plasma concentrations of 3-methoxy-4-hydroxyphenylglycol, 3,4-dihydroxyphenylacetic acid and homovanillic acid in healthy control subjects as well as in untreated schizophrenic and bipolar patients. We found that the Val158Met substitution in catechol O-methyltransferase gene influences the plasma concentrations of homovanillic and 3,4-dihydroxyphenylacetic acids. Although higher concentrations of plasma homovanillic acid were found in the high-activity ValVal genotype, this mutation did not affect the plasma concentration of 3-methoxy-4-hydroxyphenylglycol. 3,4-dihydroxyphenylacetic acid concentrations were higher in the low-activity MetMet genotype. Interestingly, plasma values 3-methoxy-4-hydroxyphenylglycol were greater in schizophrenic patients and in bipolar patients than in healthy controls. Our results are compatible with the previously reported effect of the Val158Met polymorphism on catechol O-methyltransferase enzymatic activity. Thus, our results suggest that this polymorphism, alone or associated with other polymorphisms, could have an important role in the genetic control of monoamine concentration and its metabolites. [Copyright &y& Elsevier]

Facial emotion recognition (FER) has been described to be impaired in borderline personality disorder (BPD), especially for neutral faces. Genetic modulation of FER has been studied in healthy individuals and some psychiatric conditions, but no genetic association studies have been conducted in BPD hitherto. The main objective of our study was to explore the influence of the serotonin-transporter-linked promoter region (5HTTLPR) and catechol-o-methyltransferase (COMT) Val158Met on facial emotion processing among BPD patients. To that end, seventy-six BPD outpatients were asked to complete a computer-based facial affect recognition task, representing four emotions (neutral, happy, fearful or angry). Accuracy of FER and perceptual biases were calculated. The 5HTTLPR and COMT Val158Met polymorphisms were genotyped using saliva samples. Individuals with the high-activity serotonin-transporter genotype and those with the low-activity COMT genotype had significantly more difficulties identifying neutral faces; the former showed stronger bias to perceive neutral faces as happy, and the latter, neutral faces as fearful. Interestingly, the perceptual biases observed in our patients are similar to previous reports in healthy individuals. The authors propose that the ability to accurately recognize neutral faces might be a possible endophenotype of BPD. Sex-genotype interactions were also observed in relation to angry faces and 5HTTLPR, and neutral faces and COMT Val158Met polymorphisms, in line with sex-related differences previously described for both polymorphisms in relation to FER and other cognitive and behavioral outcomes. The impact of inaccurate FER on psychosocial functioning and potential interventions are also discussed. • Genetic influence on facial emotion recognition (FER) in BPD has not been studied. • We explore the effect of 5HTTLPR and COMT Val158Met on FER in BPD. • Both polymorphisms are related to the accurate recognition of neutral faces. • Recognition of neutral faces might be proposed as an endophenotype of BPD. [ABSTRACT FROM AUTHOR]